Recent scientific investigations have shown that many chemicals used in plastics, Pharmaceuticals, pesticides, cosmetics, food additives, etc., are endocrine disrupters (EDs). EDs interfere in various ways with hormones such as estrogens to have significant adverse effects on many behavioral and physiological processes. ED effects (e.g. estrogenic or anti-estrogenic) sometimes occur at very low (picomolar to nanomolar) concentrations, especially on fetal or developing mammals (including humans). The prevalence and actions of EDs in our environment warrant the development of valid assay methods. Consequently, various governmental bodies (e.g., EPA, FDA, and ICCVAM) and proactive corporations have explicitly expressed a desire to have in vitro robotic assays for EDs, such as anti-estrogenic activity (anti-EA). However, no anti-EA assay is commercially available. To begin to meet these governmental, scientific and commercial needs, CertiChem (CCi) has preliminary data suggesting that it is feasible to develop an anti-EA robotic assay that would be valid (i.e., reliable, accurate, versatile, rapid, and cost effective) using MCF-7 cells. In this Phase I application, CCi now proposes to confirm that it is feasible to develop a robotic assay for anti-EA by first determining an optimum robotic protocol for detecting anti-EA using MCF-7 cells. CCi then proposes to estimate the reliability (reproducibility) of this assay by repeatedly (5 times) assaying over a 12 week period a limited set of reference chemicals (10) published by ICCVAM to use for validation of anti-EA assays (Specific Aim #1). CCi also proposes (Specific Aim #2) to estimate the accuracy of this assay by comparing data CCi obtains on these 10 reference chemicals with data published by ICCVAM. We strongly expect data obtained on this Phase I grant to confirm our preliminary data that this anti-EA assay is worthy of more extensive testing and development in a Phase II study to prepare it for commercialization. Development of a robotic screening assay for anti-EA is commercially, scientifically, and socially important because of the large number of chemicals (>10,000) - much less chemical mixtures - that should now be screened for anti-EA by profit, non-profit, or governmental entities. Development of a robotic assay for anti-EA is desired as part of the mission of NIEHS, EPA and ICCVAM. [unreadable] [unreadable] [unreadable]